i86 



RESEARCHES ON FUNGI 



campanulate (c/. Figs. 70, 71, 72, 75), then umbrella-shaped (Figs. 76, 

 77), and finally almost plane with a more or less revolute rim 



(Figs. 98, 99, 100, pp. 234 and 236). 

 Its disc usually remains somewhat 

 umbonate to the last. In the 

 expanded condition the pileus is 

 black all over, except for the disc 

 which is tawny and the scattered 

 scales which are usually white al- 

 though often somewhat pinkish. 

 The dimensions of the mature pileus 

 in well-grown fruit-bodies may be 

 gathered from the illustrations given 

 in Figs. 76 and 77. 



As the pileus becomes cam- 

 panulate, longitudinal striae appear 

 beneath the scales (Fig. 75). These 

 striae are produced by the incipient 

 splitting of the gills 

 down their backs. 

 As the pileus opens 

 out further, the 

 striae are converted 

 into sulcations 

 which may become 

 1 to 2 mm. deep 

 and of the same 

 width at the peri- 

 phery of the pileus 

 (Figs. 76 and 77). 

 The partial split- 

 ting of the gills 

 down their backs, 

 which is shown in 

 a vertical section in Fig. 101, A (p. 237), permits of the rapid 

 expansion of the pileus without any corresponding growth of the 

 pileus-flesh. Occasionally, as the pileus continues to expand, a 



Fig. 75. — Coprinus sterquilinus. A fruit-body on 

 sterilised horse dung. The pileus is beginning to 

 expand and, owing to the incipient splitting of 

 each gill into two halves, appears striated. Natural 

 size. 



